Reduced cerebrospinal fluid levels of the serotonin metabolite 5- hydroxyindoleacetic acid have been reported to be commonly associated with suicidal behavior. Alcoholics are known to often manifest suicidal behavior. Therefore, we compared cerebrospinal fluid levels of monoamine metabolites among alcoholics who had (N=18) or had not (N=132) attempted suicide, and controls (N=29). There were no significant differences among the three groups for cerebrospinal fluid concentrations of either 5-- hydroxyindoleacetic acid, the dopamine metabolite homovanillic acid, norepinephrine, or the norepinephrine metabolite 3-methoxy-4-- hydroxpenylglycol. However, in an expanded data set of almost 300 alcoholics there were significant differences for age of onset alcoholics who attempted suicide had an early age of onset of heavy drinking. They also had significantly more lifetime psychiatric diagnoses of major depression, antisocial personality disorder, panic, phobic disorder and more family history of alcoholism.